Aircraft often include a parking brake system that enables brake actuation in the event the aircraft is parked. In aircraft with hydraulic brakes, brake pressure may decline over time as the parking brake is engaged. Accumulators may be used to combat the decline, but parking brake force still typically degrades over time. In aircraft with electric brakes, power may be needed to maintain the brake force, which may be considerable depending upon the static friction coefficient of the brake stack. Thus, there is a need for improved parking brake systems.